In recent years, electric vehicles equipped with regenerative brakes have come into use in railway systems. However, in a case where there are few or no other electric vehicles serving as loads to consume the regenerative electric power returned from the electric vehicle through an overhead cable (a feeder cable), the regeneration effect is lost and the regenerative brake may become unusable. To address such a problem, a system has been proposed in which a power storage apparatus is provided for the regenerative electric power to be stored when there is no electric vehicle consuming the regenerative electric power (Patent Literature 1). In the system described in the proposal, when an overhead cable voltage (a feeder voltage) is equal to or more than a charging start voltage, an operation starts that converts the regenerative electric power in order to charge a power storage apparatus, and when the overhead cable voltage is equal to or less than a discharging start voltage, an operation starts that converts the power charge in the power storage apparatus and discharges it through the overhead cable. However, when the charging start voltage is fixed, the overhead cable voltage may be increased while no load is being applied in the early morning or at night and it may reach the charging start voltage. This causes a cross current to occur even though regeneration is not occurring. The cross current is a current that occurs when the power supplied from an electric power substation is consumed (i.e. the power storage apparatus is charged) instead of the regenerative electric power of the electric vehicle being consumed. In the system of Patent Literature 1, the overhead cable voltage is monitored for a certain time period to calculate an average voltage, and a voltage value that is higher than the average voltage for a certain number of voltages is set as the charging start voltage. Thus, a cross current can be prevented from occurring.
In the system of Patent Literature 1, the surplus amount of regenerative electric power (the regenerative electric power not fully consumed by the other electric vehicles while they are running) is accumulated in the power storage apparatus. However, a configuration can be envisioned in which the surplus regenerative electric power is consumed, for example, by various types of loads (illumination devices, air conditioners, elevators, and the like) in the station. In this configuration where the regenerative electric power is consumed by loads in the station, the power storage apparatus becomes unnecessary, and the regenerative electric power is then effectively used at a lower cost.